The invention relates to an air valve for use in an electrically controlled, intermittently operating fuel injection arrangement for internal combustion engines having externally supplied ignition, wherein the apportioned fuel quantity is injected into the suction tube of the intake manifold, within which an air metering member and an arbitrarily manipulatable throttle flap are located in succession, and within which the suction tube sections respectively upstream and downstream of the throttle flap are interconnected via a bypass whose cross-sectional area is variable by means of the air valve. The air valve is provided with a membrane which divides the air valve housing into two chambers in one of which is located a movable valve component that controls the cross-sectional area of the bypass. The valve component is urged toward an open direction by a guide spring, via a connecting member guided by a guide plate.
Air valves which respond, for example, to the pressure drop in the intake manifold resulting from the sudden closing of the throttle valve during over-running operation of the internal combustion engine, in order to influence the fuel-air mixture by delivering a small quantity of air, sufficient to maintain combustion in the individual cylinders of the combustion engine during over-running operation with the throttle valve closed, are well known. This type of air valve is not suitable, however, to enhance the starting condition of the internal combustion engine. Thus, to guarantee reliable and positive starting of the internal combustion engine, it is advantageous to supply the internal combustion engine with two or three times the normal quantity of air, and hence of the fuel-air mixture, needed during idling.